1. Field
The handling of high pressure fluids presents particular problems in any device in which substantial reduction of pressure occurs. High pressure liquids often cavitate within turbines, valves and the like, resulting in pitting of critical surfaces. Also, a rapid drop in pressure of a super-atmospheric gas stream often results in inordinately loud noises as the gas approaches or exceeds sonic velocities. These problems can be overcome by gradually dropping the pressure by subjecting the fluid to a series of minor reductions in pressure, for example, by placing a number of orifices of decreasing orifice diameter in the fluid stream, or by subjecting the fluid to substantial conduit friction, for example, by passing the fluid through channels, passageways and the like having a very high wall-area to volume ratio.
2. State of the Art
The concept of utilizing narrow passageways in lieu of orifices to effect pressure reduction or to control fluid flow has been practiced in the art. The control of low volume fluid flow is illustrated by the device disclosed in U.S. Pat. No. 1,964,300 of Perry, et al wherein a single, long-length passageway was utilized to control gas flow to a pilot burner.
In Mittendorf, et al, U.S. Pat. No. 2,021,079, a long-length, narrow passageway is utilized in a pressure reduction device. A single tortuous path is provided by grooving adjacent disks so that an interconnecting passageway is formed through a stack of disks.
The concept of utilizing a long passage has been further applied to axially actuated valves in which a plurality of tortuous paths are presented to a high pressure stream.
In U.S. Pat. No. 3,514,074 the fluid flow is subdivided into a plurality of individual streams in respective passageways having a long-length to diameter ratio, while in U.S. Pat. No. 3,513,864 the high pressure fluid flows a tortuous course through a skeletal, disk-baffle grid assembly. The devices described in both patents have adjacent disks having radial separators extending along the disk faces. At least some of the disks of the U.S. Pat. No. 3,513,864 are perforated, while disks of the U.S. Pat. No. 3,514,074 have furrows separated from one another by the face surfaces in sealing contact between adjacent furrows, the furrows changing direction of fluid flow substantially in a horizontal plane.
A single, narrow passageway cannot be effectively utilized to handle a high pressure stream having a high rate of flow. Furthermore, devices which utilize individual or discrete passages tend to plug whenever the fluid contains solid matter. While the devices of the prior art are effective for their intended purpose, an easily manufactured device for handling high pressure streams of large volumes does not exist.